Processing arrangements comprising a processing unit and a memory unit are widely known. For example, most electronic devices such as computers or consumer electronic devices comprise a microprocessor and a BIOS (basic input output system) memory unit comprising processing instructions performed after providing the microprocessor with an operating voltage, i.e., after switching the device on.
Another example of processing arrangements of the described kind are memory card devices such as flash memory cards, in which a non-volatile memory unit is accessed by means of an integrated microcontroller acting as processing unit.
During startup and operation of such processing arrangements temporary problems or faults can occur. For example, it may take more time for the memory unit to become operational than it takes for the processing unit.
A processing unit receiving no data or an unexpected data value from a memory unit due to a temporary fault will typically perform some unwanted operation, often resulting in a malfunctioning of the entire processing arrangement.
For example, a memory card device trying to access its memory unit after connection of the device to a host system may crash, because a power supply from the host system to the memory card device is not stable at the time of the first access. As a consequence, the memory card device may not respond as expected by the host system and is unavailable for storing, receiving or sending data.
In order to overcome such and similar problems, one can design a separate detection circuit that is capable of detecting a temporary fault or error. On detection, the detection circuit can then stop the processing unit, for example by providing a suitable control signal to it or by stopping a clock signal of the processing arrangement.
However, such detection circuits require additional electronic components and thus space in the processing arrangement. As a consequence, the processing arrangement becomes more complex and thus more expensive.
Another disadvantage of such a solution is that it cannot be changed after the design of the processing arrangement has been completed. For example, it is impossible to introduce new fixing operations for responding to a detected temporary problem after the design stage of the processing arrangement.
In one aspect, the present invention describes a processing arrangement with a simple and flexible design that is capable of performing a fixing operation. In a further aspect, the invention provides a memory card device with a simple and flexible design that is capable of performing a fixing operation. In yet another aspect, the invention describes methods for manufacturing and operating processing arrangements in accordance with the invention.